Atrial fibrillation (AF) is a common arrhythmia with increasing incidence with age and presence of heart disease. If left untreated in a patient, the risk of stroke, heart attack and heart failure is very high, and after treatment, risk still remains high. Several known causes of increased risk of AF are the functional, structural, and electrical changes in the heart that come with age and the presence of heart disease (myocardial infarction, cardiomyopathy, hypertrophy, congestive heart failure, etc.). These changes result in abnormal conduction of electrical impulses in the heart.